EPR Study of the Mn-Doped Magnesium Titanate Ceramics

Manganese-doped magnesium titanate ceramic samples obtained by a solid-state reaction via sintering in the air from a mixture of MgO and TiO2 powders of different molar ratios were analyzed by electron paramagnetic resonance (EPR) technique. The EPR signals of Mn2+ ions (S = 5/2, І = 5/2) in crystal phases of MgO, Mg2TiO4, and MgTiO3 were detected. We have obtained the following spin Hamiltonian parameters for Mn2+ ions: g = 2.0015, A ~ 81 ∗ 10-4 cm-1 (in MgO phase); g = 2.0029, A ~ 73.8 ∗ 10-4 cm-1, b2 0 = 35 ∗ 10-4 cm-1 (in Mg2TiO4 phase); g = 2.004, A ~ 79 ∗ 10-4 cm-1, b2 0 = 165 ∗ 10-4 cm-1 (in MgTiO3 phase). Despite the presence of Mn4+ centers in both Mg2TiO4:Mn and MgTiO3:Mn ceramics confirmed by previous optical studies, no EPR signals related to Mn4+ ions (S = 3/2, І = 5/2) were found. The Mn2+ EPR signals are proposed as structural probes in manganese-doped magnesium titanate ceramics.

Cluster assembly times as a cosmological test

The abundance of galaxy clusters in the low-redshift universe provides an important cosmological test, constraining a product of the initial amplitude of fluctuations and the amount by which they have grown since early times. The degeneracy of the test with respect to these two factors remains a limitation of abundance studies. Clusters will have different mean assembly times, however, depending on the relative importance of initial fluctuation amplitude and subsequent growth. Thus, structural probes of cluster age such as concentration, shape or substructure may provide a new cosmological test that breaks the main degeneracy in number counts. We review analytic predictions for how mean assembly time should depend on cosmological parameters, and test these predictions using cosmological simulations. Given the overall sensitivity expected, we estimate the cosmological parameter constraints that could be derived from the cluster catalogues of forthcoming surveys such as Euclid, the Nancy Grace Roman Space Telescope, eROSITA, or CMB-S4. We show that by considering the structural properties of their cluster samples, such surveys could easily achieve errors of Δσ8 = 0.01 or better.

Recent Progress in Polynuclear Ruthenium Complex-Based DNA Binders/Structural Probes and Anticancer Agents

Ruthenium complexes have stood out by several mononuclear complexes which have entered into clinical trials, such as imidazolium [trans-RuCl4(1H-imidazole)(DMSO-S)] (NAMI-A) and ([Ru(II)(4,4'-dimethyl-2,2'-bipyridine)2-(2(2'-,2'':5'',2'''-terthiophene)-imidazo[4,5-f] [1,10]phenanthroline)] 2+) (TLD-1433), opening a new avenue for developing promising ruthenium-based anticancer drugs alternative to Cisplatin. Polynuclear ruthenium complexes were reported to exhibit synergistic and/or complementary effects: the enhanced DNA structural recognition and DNA binding as well as in vitro anticancer activities. This review overviews some representative polynuclear ruthenium complexes acting as DNA structural probes, DNA binders and in vitro anticancer agents, which were developed during last decades. These complexes are reviewed according to two main categories of homo-polynuclear and hetero-polynuclear complexes, each of which is further clarified into the metal centers linked by rigid and flexible bridging ligands. The perspective, challenges and future efforts for investigations into these exciting complexes are pointed out or suggested.